The Rarest Event Ever Recorded?

[beecee]

https://phys.org/news/2019-04-dark-detector-rarest-event.html

Dark matter detector observes rarest event ever recorded

by Rensselaer Polytechnic Institute:

How do you observe a process that takes more than one trillion times longer than the age of the universe? The XENON Collaboration research team did it with an instrument built to find the most elusive particle in the universe—dark matter. In a paper to be published tomorrow in the journal Nature, researchers announce that they have observed the radioactive decay of xenon-124, which has a half-life of 1.8 X 1022 years.

"We actually saw this decay happen. It's the longest, slowest process that has ever been directly observed, and our dark matter detectorwas sensitive enough to measure it,"

more at link......

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the paper:

https://www.nature.com/articles/s41586-019-1124-4

Observation of two-neutrino double electron capture in 124Xe with XENON1T: 

 

Abstract:

Two-neutrino double electron capture (2νECEC) is a second-order weak-interaction process with a predicted half-life that surpasses the age of the Universe by many orders of magnitude1. Until now, indications of 2νECEC decays have only been seen for two isotopes2,3,4,5, 78Kr and 130Ba, and instruments with very low background levels are needed to detect them directly with high statistical significance6,7. The 2νECEC half-life is an important observable for nuclear structure models8,9,10,11,12,13,14 and its measurement represents a meaningful step in the search for neutrinoless double electron capture—the detection of which would establish the Majorana nature of the neutrino and would give access to the absolute neutrino mass15,16,17. Here we report the direct observation of 2νECEC in 124Xe with the XENON1T dark-matter detector. The significance of the signal is 4.4 standard deviations and the corresponding half-life of 1.8 × 1022 years (statistical uncertainty, 0.5 × 1022 years; systematic uncertainty, 0.1 × 1022 years) is the longest measured directly so far. This study demonstrates that the low background and large target mass of xenon-based dark-matter detectors make them well suited for measuring rare processes and highlights the broad physics reach of larger next-generation experiments

[Strange]

Another good article here, with a lot more background information: https://www.forbes.com/sites/startswithabang/2019/04/24/dark-matter-search-discovers-a-spectacular-bonus-the-longest-lived-unstable-element-ever/#4cc56d32c0fc

[swansont]

 

Quote

 

Dark matter detector observes rarest event ever recorded

 

Ugh. Headline editors.

The probability may be low for a single decay, but the event is not rare if you have a lot of the isotope. If you had a mole, you'd have 33 decays per year.  Less rare than payday (for me, anyway)

 

 

[StringJunky]

1 hour ago, swansont said:

 

Ugh. Headline editors.

The probability may be low for a single decay, but the event is not rare if you have a lot of the isotope. If you had a mole, you'd have 33 decays per year.  Less rare than payday (for me, anyway)

 

 

Duh!

[peterwlocke]

now here is a pleb question but how can you see this if it takes longer then the universe like has it gone on to the next halflife if so how. 

isn't the universe older then 1.8 times 1022 years like that is not even the time the earth has been around.

P.S. what is different about this isotope.

Edited April 25, 2019 by peterwlocke

[Strange]

5 minutes ago, peterwlocke said:

now here is a pleb question but how can you see this if it takes longer then the universe like has it gone on to the next halflife if so how. 

The half-life is longer than the life of the universe. That means the time it would take for half the atoms in a sample to decay.

You can calculate the half-life from looking at the rate at which atoms decay without having to wait for one half-life.

6 minutes ago, peterwlocke said:

isn't the universe older then 1.8 times 1022 years like that is not even the time the earth has been around.

1.8x10²² is 18,000,000,000,000,000,000,000 ie 18 sextillion years. The universe is merely 1.38x10¹⁰ = 13,800,000,000 ie. 13.8 billion years old.

[peterwlocke]

oh, it looked to me like that because there was no to the power of I should have noticed it was odd sci notation. ty